In December, the Sunday Telegraph carried a long and prominent feature written by Christopher Booker and Richard North, titled: Questions over business deals of UN climate change guru Dr Rajendra Pachauri.

The subtitle alleged that Pachauri has been "making a fortune from his links with 'carbon trading' companies". The article maintained that the money made by Pachauri while working for other organisations "must run into millions of dollars".

It described his outside interests as "highly lucrative commercial jobs". It proposed that these payments caused a "conflict of interest" with his IPCC role. It also complained that we don't know "how much we all pay him" as chairman of the IPCC.

The story (which has subsequently been removed from the Sunday Telegraph's website) immediately travelled around the world. It was reproduced on hundreds of blogs. The allegations it contained were widely aired in the media and generally believed. For a while, no discussion of climate change or the IPCC appeared complete without reference to Pachauri's "dodgy" business dealings and alleged conflicts of interest.

There was just one problem: the story was untrue.

It's not just that Pachauri hadn't been profiting from the help he has given to charities, businesses and institutions, his accounts show that he is scrupulous to the point of self-denial. After the Sunday Telegraph published its story, the organisation for which Pachauri works - a charity called The Energy and Resources Institute (TERI) - asked the auditors KPMG to review his financial relationships. Today, for the first time, the Guardian is publishing KPMG's report.

KPMG studied all Pachauri's financial records, accounts and tax returns, as well as TERI's accounts, for the period 1 April 2008 – 31 December 2009. It found that any money paid as a result of the work that Pachauri had done for other organisations went not to him but to TERI. None of the money was paid back to him by TERI: he received only his annual salary, which is £45,000.

His total additional income over the 20 months reviewed by KPMG amounted to the following:

• A payment of 20,000 rupees (£278) from two national power commissions in India, on which he serves as director;

• 35,880 rupees (£498) for articles he has written and lectures he has given;

• A maximum of 100,000 rupees - or £1,389 - in the form of royalties from his books and awards.

In other words, he made £45,000 as his salary at TERI, and a maximum of £2,174 in outside earnings. So much for Pachauri's "highly lucrative commercial jobs" amounting to "millions of dollars".

Amazingly, the accounts also show that Pachauri transferred a lifetime achievement award he was given by the Environment Partnership Summit - 200,000 rupees - to TERI. In other words, he did not even keep money to which he was plainly entitled, let alone any money to which he was not.

As for "how much we all pay him" as chairman of the IPCC, here is the full sum:

£0.

It wouldn't have been difficult for the Sunday Telegraph to have discovered this. It's well known that the IPCC does not pay its chairmen. His job at TERI is not a "sideline", as many of his opponents maintain. It is his livelihood.

This is a reflection of the lack of support given by governments to the IPCC. Its opponents like to create the impression that it's an all-powerful body on the verge of creating a communist/fascist world government. In reality it's a tiny, underfunded organisation which can't even pay its own chairman.

Compare Pachauri's total earnings to the kind of money made by the head of any of the UN agencies, or of the World Bank or the IMF, and you'll see that he receives one-fifth or one-tenth of the cash raked in by his peers.

KPMG concluded:

No evidence was found that indicated personal fiduciary benefits accruing to Pachauri from his various advisory roles that would have led to a conflict of interest.

The Sunday Telegraph, in other words, maligned a scrupulously honest man.

When Pachauri approached the Sunday Telegraph, asking for a retraction, he was rebuffed. Far worse, the journalists pursued the attack in a series of further articles and blogposts. To me it looks as if Richard North was pursuing a vendetta against the IPCC chair. In a post in February, he wrote:

Pachauri is on the ropes but he ain't down yet. The view is it will take one more 'killer blow' to fell him .. and it looks as if its been found! … R K Pachauri needs to be acquainted with the first rule of politics - DFWN ... since it is a family blog, you'll have to work it out for yourselves.

The abbreviation stands for "Don't fuck with North". In truth Pachauri had done no such thing: he had merely asked, politely and mildly, for the false allegations to be corrected.

Because the issue took so long to resolve, the total legal costs for the paper - the fees for its own lawyers and Pachauri's - run into six figures.

Has the Sunday Telegraph's apology solved the problem? Some hope.

North has reacted to it with a new blogpost, also widely reproduced on the web, in which he refers to the Sunday Telegraph apology as a "non-apology". He claims: "the article was sound, all the substantive facts are correct and the paper stands by them."

He goes on to suggest that Pachauri was indeed "corrupt or abusing his position as head of the IPCC" and maintains that the accusation that Pachauri has made millions of dollars "stands uncorrected". North fails to provide any evidence to support this falsified claim.

North also suggests that Pachauri's hiring of a firm of libel lawyers in order to obtain this apology "tells you all you need to know" about him. In reality it tells you that Pachauri had exhausted his other options. He was desperate to put the record straight, but despite the incontrovertible evidence he provided, which showed that the story was false, the paper had refused to published a retraction. Pachauri threatened legal proceedings as a last resort.

So what can Pachauri do? There is now a large community of people - those who deny that man-made climate change is taking place - who appear to be out to get him. His crime is being chairman of the IPCC. That, as far as they are concerned, makes him guilty of any charge they wish to throw at him. They appear determined to keep repeating the falsehoods they have been circulating since December. We can expect this smear campaign to continue, and to become ever more lurid as new charges are invented.

The best we can do is to set out the facts and appeal to whatever decency the people spreading these lies might have, and ask them to consider the impact of what they have done to an innocent man. Will it work? I wouldn't bet on it. As we have seen in the United States, where some people (often the same people) continue to insist that Barack Obama is a Muslim and was born abroad, certain views are impervious to evidence.